---

  Background and Objective: Staphylococcus aureus is known as an important pathogen causing a variety of bacterial infections. Treatment of this bacterium with antibiotics has led to antibiotic-resistancey, especially against methicillin (MRSA) and more recently rare resistance against vancomycin. The aims of this study were to determine nasal carriage rates of S. aureus in Meshgin Shahar Valiasr hospital’s personnel and to determine antibiotic-resistance patterns in the mentioned isolates.

  Methods: Staphylococcus aureus isolates were collected from the nose of 200 hospital personnel in Meshgin Shahar Valiasr hospital in a 2 month period in 2006. Antibiotic sensitivity of the collected strains were tested against antibiotics used in routine treatment of S. aureus infections. Oxacillin agar was also used to screen for MRSA according to NCCLS recommendation.

  Results: Our results showed there were 45% and 16% nasal carrier rate for S. aureus and MRSA (methicillin resistant staphylococcus aureus) strains, respectively in hospital personnel. Thirty two isolates were able to grow in oxacillin agar media, indicating 35% MRSA strains. Antibiotic resistant pattern of strains in disks method were recorded as follows: 35% to oxacillin, 97.8% to penicillin, 34% to erythromycin, 2.1% to chloramphenicol, 39.36% to tetracycline, 11.7% to gentamicin, 30.85% to trimetohoprim sulfamethoxazol and 19% to clindamycin. All of the isolates were sensitive to vancomycin and ciprofloxacin.

Conclusion: In this study, nasal carriage rate of Staphylococcus aureus among hospital Personnel was more than community expected rate (%40) and lower than hospital expeeted rate (%50-80). All of the test strains were sensitive to Vancomycin.

---

  Background & Objectives: Staphylococci are among common causes of community acquired and nosocomial infections around the world. Over the last decade, the resistance of these bacteria in hospital environments is increasing to various antibiotics such as vancomycin. The aim of present study was to determine the antimicrobial resistance pattern and Minimum Inhibitory Concentration (MIC) values among a clinical collection of staphylococci isolated from hospitalized children in Tabriz.

  Methods: In this prospective and descriptive study, 88 staphylococcal isolates including 53 S. aureus and 35 coagulase-negative staphylococcus species were recovered from various clinical specimens referred to microbiology laboratory of Children Hospital during study period (April 2011 to March 2012). Susceptibility of the isolates against 15 different antimicrobial agents and MIC values of vancomycin was tested using standard disk diffusion and E-test methods respectively.

  Results: According to the results of drug susceptibility testing, vancomycin and rifampin were the most effective but clindamycin and penicillin were the least effective drugs against tested isolates. Accordingly, the prevalence of methicillin resistant Staphylococcus aureus (MRSA) strains was determined more than 80%. According to MIC values, 13.2% of S. aureus and 3.3% of coagulase-negative staphylococcus isolates showed intermediate resistance to vancomycin. None of the isolates was fully resistant to vancomycin isolates in this study.

  Conclusion: Although fully vancomycin resistant staphylococci was not found among tested isolates in this study, there was VISA strains. Since there are reports on the emergence of VRSA strains from Iran and other countries, it is necessary for the clinician to care in prescription of vancomycin as a selective drug against staphylococcal infections. Moreover, the necessity of MIC measurement in determining of vancomycin susceptibility is more apparent.

---

Background & objectives: Enterococcus spp. are predominant in the faecal microflora which enter the environment directly or through wastewater. These bacteria play an important role in the development of nosocomial infections due to their ability to acquire resistance genes and their transmission to other bacteria, particularly Staphylococcus aureus. The aim of this study was to identify the prevalence of vancomycin-resistant enterococci (VRE) and to detect van A, van B and van C1/C2 genes in VRE strain isolated from environmental samples of the in southern Fars province.
Methods: This cross-sectional study was carried out on 155 Enterococcus spp isolates collected from environmental samples (hospital wastewaters and surface waters) in different areas of Larestan and Jahrom cities. Isolates were identified and confirmed as Enterococcus spp. using the membrane filtration method, selective growth on Kenner Fecal Streptococcus Agar (KF) medium and biochemical tests. The disk diffusion test and Macro Broth dilution method based on CLSI guidelines were used to determine antimicrobial susceptibility against conventional antibiotics and vancomycin and to measure the minimum inhibitory concentration (MIC), respectively. Finally, the presence of van A, van B and van C1/C2 genes in VRE strains was determined by multiplex PCR technique.
Results: Out of all of Enterococcus spp. isolates, 41 cases (26.45%) were belonged to E.faecalis, 6 cases (3.87%) to E.faecium and 108 cases (69.68%) to non-faecalis and non-faecium. In total, 46 isolates (29.67%) were resistant to vancomycin and 4 isolates showed MIC ≥128 μg/ml. Resistant to all types of antibiotics was observed in 4 isolates (8.70%). Further, 2 isolates (50%) had vanA gene and 2 isolates (50%) had vanB gene, but vanC1/C2 genes were detected in none of them.
Conclusion: The results indicated that the VRE strains are widespread in the studied area, therefore there is an urgent need for prudent use of vancomycin and implementation of control measures to prevent the environmental spread of VRE strains.